GREEK

Well at least you are smart enough to figure out where it all came from anyway....................The Greeks.
The Greek Alphabet contains 24 letters,and if placed in a circle it makes the Compass with the 15* angle between each.IE. 0*,15*,30*,45*60*75*,90*....to .....180*..... to 270*.....to 360* or 0*.
I could get deep fast now,but will try and keep it fairly simple.

A statement in your "ANGULAR MEASUREMENTS" link stated that the width of the thumb at arms length was approximately 2 degrees. I used that to check out a "rule of thumb" that I learned many years ago - that the sun will travel 4 fingers at arms length in 30 minutes. In other words, when the sun is 4 fingers at arms length above the horizon, it's time to bring in the mule. The sun will set in 30 minutes.

Well, it turned out to be a pretty good rule of thumb. There are 48 30-minute time periods in one 360 degree rotation of the sun (earth). That divides out to 7.5 degrees per 30 minutes. Four widths of the thumb would be 8 degrees, slightly more than four fingers since the thumb is slightly larger than the fingers.